OPTICAL FAULT MONITORING

• US 20110062309A1
• Filed: 09/14/2009
• Published: 03/17/2011
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yee, Dawson
• Granted Patent: US 8,330,134 B2
• Time in Patent Office: Days
• US Class Current: 250/201.1
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0228 Control of working procedures; Failure detection; Spectral bandwidth calculation
• CPC Class Codes: G01J 1/32 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00

Abstract

Various embodiments related to monitoring for optical faults in an optical system are disclosed. For example, one disclosed embodiment provides, in an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults. The method includes detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor, and comparing an intensity of light detected to one or more threshold intensity values. The method further includes identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values, and modifying operation of the optical system.

Claims

1. In an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults, the method comprising:

detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor;

comparing the intensity of light detected to one or more threshold intensity values;

identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values; and

modifying operation of the optical system based upon the optical system fault condition.

2. The method of claim 1, wherein identifying the optical system fault condition includes determining that the intensity of light detected is less than a threshold value.

3. The method of claim 2, wherein modifying operation of the optical system includes performing a shutdown operation to the optical system.

4. The method of claim 1, wherein identifying the optical system fault condition includes determining that the intensity of light detected is greater than a threshold value.

5. The method of claim 4, wherein modifying operation of the optical system includes displaying a warning message on a display device.

6. The method of claim 5, further comprising detecting no response to the warning message, and performing a shutdown operation to the optical system.

7. The method of claim 6, further comprising, after performing the shutdown operation, detecting a response to the warning message and in response, returning the optical system to a normal operating state.

8. An optical device, comprising:

a light source configured to output a beam of light;

a diffractive optical element configured to receive the beam of light on a light-source side of the diffractive optical element and to diffract the beam of light to form a structured pattern;

a photodetector directed toward the light-source side of the diffractive optical element, the photodetector configured to measure an intensity of light traveling from the light-source side of the diffractive optical element; and

a controller configured to detect an optical fault condition by monitoring the intensity of light as measured by the photodetector and comparing the intensity of light to one or more threshold values.

9. The optical device of claim 8, wherein the controller is further configured to change a power state of the optical device if an upper threshold value is met.

10. The optical device of claim 8, wherein the controller is further configured to change a power state of the optical device if a lower threshold value is met.

11. The optical device of claim 8, wherein the controller is further configured to apply a response action upon detecting the optical fault condition.

12. The optical device of claim 11, wherein the response action includes one or more of changing a power state of the optical device and displaying a warning message on a display device.

13. The optical device of claim 8, wherein the light source comprises a laser diode.

14. The optical device of claim 8, wherein the optical device is a depth-sensing camera.

15. In a depth-sensing camera comprising a light source, a light outlet, and a diffractive optical element disposed between the light source and the light outlet, a method of monitoring for optical faults, the method comprising:

detecting via a photodetector located on a light-source side of the diffractive optical element an intensity of light traveling from the diffractive optical element;

comparing the intensity of light to one or more threshold values;

if the intensity of light is less than a first threshold value, identifying an optical fault due to a change in a location of the diffractive optical element and applying a first corrective action; and

if the intensity of light is greater than a second threshold value, identifying an optical fault due to a physical object located on a light-outlet side of the diffractive optical element, and in an optical path of the diffractive optical element, and applying a second corrective action.

16. The method of claim 15, further comprising, if the intensity of light is outside of an operating range of accepted values, identifying an optical fault due to degraded performance of the diffractive optical element and applying a third corrective action.

17. The method of claim 15, wherein applying the first corrective action includes performing a shutdown operation to the depth-sensing camera.

18. The method of claim 15, wherein applying the second corrective action includes displaying a warning message on a display device.

19. The method of claim 18, further comprising detecting no response to the warning message within a predetermined time duration, and performing a shutdown operation to the depth-sensing camera.

20. The method of claim 19, further comprising, upon applying the shutdown operation, detecting a response to the warning message and in response, returning the depth-sensing camera to a normal operating state.